New Research

Quantum interface connecting various physical systems

In various physical systems including materials and light, elemental quantum operations have been mostly demonstrated so far. Some of those are used for complex tasks nowadays. A significant example is a prototype of cloud quantum computing service offered in north America. In order to realize an actual global network, however, it is necessary to have quantum interfaces for connecting the physical systems that have been developed independently.

Our group started quantum information research in its early stage (since 1990’s) both from theoretical and experimental aspects. Recently, we mainly focus our research on quantum interfaces. Materials exhibit quantum effects only in an ultra-cold environment, while photons show purely quantum effects even at the room temperature. In addition, photons can carry large amounts of information at high speed. Therefore, photons are considered to be the best candidate for the quantum information carrier. On the other hand, materials play an important role in a long-term storage of the quantum information. Thus, the quantum interface that links photons with the material quantum memories is vital for the future quantum information technology.

For the realization of such quantum interfaces, we recently demonstrated a quantum correlation between a telecom photon and a cold atomic ensemble. Our research activities have been published in high impact journals such as Nature, Nature series, and Physical review letters, etc. We are now trying to develop more complex quantum interfaces toward the global quantum network.